This Dietitian Loves Her Coffee: Here’s Why

I’ve gotten a lot of comments from surprised people when they see that I’m drinking coffee, because they falsely believe that it’s a “bad” habit.  It’s true that caffeine is an addictive stimulant and it’s also true that it has been linked to some pretty negative health problems, including: recurrent migraines, anxiety, insomnia, GERD, increased symptoms of hypoglycemia, fibrocystic breast symptoms, and urinary tract disorders in the past. However, several of these concerns have been blown way out of proportion. Researchers are now finding more and more benefits to my beloved coffee.

One thing that definitely hasn’t changed is that pregnant women should not consume more than 200 mg of caffeine a day, because it almost certainly increases the risk of miscarriage and low birth weight.

How caffeine affects you mentally and emotionally depends on exactly how much you’re drinking. If you’re drinking a cup or two a day (about 200 mg of caffeine), it might improve your mental acuity, reaction time, and mood state. Specifically, 200 mg of caffeine increases happiness, energy, alertness, and sociability. Once you get to around 400 or 500 mg a day though, it’s likely to have an adverse effect on your performance and mood, and can cause the development of anxiety, nervousness, and jitteriness.

If you’ve ever wondered how caffeine puts a little pep in your step, it temporarily binds to the adenosine receptors in your brain. Adenosine is a natural sedative produced in the brain that causes drowsiness, and caffeine blocks the doorway so that it can’t get in and make you sleepy. Some people think that caffeine doesn’t actually stimulate us much at all, it just takes the edge off by easing withdrawal symptoms. In essence, this theory posits that we are no more alert that we would be if we’d never consumed caffeine in the first place.

The blood vessels in your brain dilate when you have a headache and many medications for headaches contain caffeine, because it makes those vessels constrict. Caffeine is also a mild analgesic. Among people who are genetically susceptible to migraines, though, it seems that caffeine increases the frequency of those particularly nasty headaches.

At one time, caffeine was linked to pancreatic cancer, but thankfully that research has been proven faulty. Coffee has recently been linked to a decreased risk of liver cancer, though. The European Prospective Investigation into Cancer and Nutrition followed 520,000 people in 10 countries for 15 years. Researchers compared the coffee intake of 125 healthy participants who were later diagnosed with the most common form of liver cancer. They discovered that those who drank at least 2 ½ cups of coffee a day had a 75% lower risk of having developed the cancer compared to those who drank no more than 1 ¼ cups a day. There’s no way to know if decaffeinated will do the trick, because the researchers didn’t separate caffeinated and decaffeinated coffee in this study.

In many studies, 4-6 cups of coffee a day (whether regular or decaf) seems to reduce the risk of developing type 2 diabetes – by as much as 30%, actually. Why? It might be because it reduces insulin resistance, which is important because insulin resistance doesn’t just lead to the development of diabetes, but also heart disease and gout. Or it might be that the chlorogenic acid in coffee delays the absorption of glucose from the intestines. There is no evidence that coffee will slow down the progression of diabetes or reverse the disease once it has developed, though.

It is true that coffee causes a transient spike in blood pressure, but it does not seem to have any impact on whether or not someone goes on to develop hypertension. If you already have high blood pressure, it makes sense to limit or avoid caffeine. Contrary to what patients have told me over the years, there actually isn’t much evidence that caffeine increases heart arrhythmias, such as atrial fibrillation.

If you’ve ever browsed the rows of unregulated supplements at any major retailer, you’ve probably noticed that caffeine holds a prominent place on the “weight loss aid” shelf. In reality, while it seems possible that caffeine might aid in weight loss since it seems to increase fat oxidation and thermogenesis, there is no evidence that it leads to weight loss over the long-term. This might be because we either develop a tolerance to it after a while or because we unconsciously compensate for it by eating more food later. Our body really, really likes to stay at a steady weight and will do all kinds of interesting and frustrating things to make sure that we don’t lose too many pounds. A moderate amount of caffeine does seem to increase aerobic physical endurance and anaerobic performance, as well as reduce our perception of muscle pain.

Only caffeinated coffee seems to decrease the risk of Parkinson’s disease. In a very large and well-done study, it decreased the risk by about 40% among people who drank between one and three cups a day. However, like always, it’s possible that the coffee drinkers all had something else in common. Once someone has developed Parkinson’s disease, caffeine unfortunately doesn’t seem to slow the progression.

At the same time that scientists first discovered that caffeine decreased the risk of developing Parkinson’s disease, research seemed promising in regards to dementia. However, as more studies have been done, the results have gotten murkier and murkier. There’s conflicting evidence so we will just have to wait and see if a consensus can be reached.

Caffeine likely decreases the risk of gallstones. In one study, both males and females who drank two or three cups of coffee a day had a 20% lower risk of developing gallstones over 20 years compared to people who drank done. In a study that only included men, the decrease in risk was even more impressive – 40%.

Do you remember the Red Bull and Vodka thing in the early 2000s? Or the Irish Coffee thing of…last night? The problem is that caffeine makes you feel less drunk, but it doesn’t actually sober you up in the least. It just makes you believe that your reaction time and judgment are OK, and you can see why that’s a pretty dangerous situation to find yourself in.

One last thing, it turns out that caffeinated beverages don’t lead to dehydration. If you don’t normally drink caffeine and then one day you decide to go hog wild and guzzle five venti lattes, your urine output is going to increase for a few hours. However, for someone like me who has been drinking 4 to 5 cups a day for many years, it’s not going to cause the same reaction. In fact, the Institute of Medicine has concluded that caffeinated beverages appear similar to non-caffeinated beverages when it comes to meeting fluid needs.

How your body reacts to caffeine seems to be a pretty individualized thing – some people swear that a cup of coffee after dinner doesn’t interrupt their sleep while others insist that they can’t have a drop after noon. If you feel OK and sleep well, and you’re not drinking multiple pots of coffee or cases of energy drinks every day, there’s probably not too much of a reason for concern about your caffeine intake, as long as you aren’t pregnant, have high blood pressure, or suffer from GERD. In fact, a few cups a day might just be a boon your health.